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    <title>简易选项卡</title>
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            <li class="actived">第一课</li>
            <li>第二课</li>
            <li>第三课</li>
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            <li style="display:block">
                <span>网页特效原理分析</span>
                <span>响应用户操作</span>
                <span>动手编写第一个JS特效</span>
                <span>展开/收缩播放列表效果</span>
                <span>网页换肤效果</span>
                <span>引入函数</span>
            </li>
            <li>
                <span>改变网页背景颜色</span>
                <span>for循环配合if判断</span>
                <span>戛纳印象效果</span>
                <span>innerHTML的使用</span>
                <span>className的使用</span>
                <span>戛纳印象效果</span>
                <span>字符串连接</span>
            </li>
            <li>
                <span>改变网页背景颜色</span>
                <span>for循环配合if判断</span>
                <span>戛纳印象效果</span>
                <span>innerHTML的使用</span>
                <span>JavaScript组成</span>
                <span>戛纳印象效果</span>
                <span>字符串连接</span>
                <span>改变网页背景颜色</span>
                <span>for循环配合if判断</span>
                <span>定时器应用：数码时钟</span>
                <span>函数详解：函数</span>
                <span>className的使用</span>
                <span>戛纳印象效果</span>
                <span>程序调试方法</span>
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